64 BOTANY 



found in plants of the Gymnosperm and higher families. 

 The early trees, however, belonged to a much lowlier 

 family, to the Lycopodiacese, which ranks below the 

 ferns and is now represented by the Club-moss or Lyco- 

 podium, and the delicate moss-like Selaginella, which 

 is so often cultivated in greenhouses. It is improbable 

 that any living form is actually descended from these 

 giant tree forms of the coal forests, though sometimes 

 the modern genera are spoken of as the degenerate 

 representatives of the old stock. A truer statement of 

 the case would be that the family, as a whole, reached 

 its acme of success in these early times, and that the 

 dominant position in the forests having been won from 

 them by the higher plants as these evolved, the only 

 representatives of the group for winch there remained 

 room in the scheme of things are the small green herbs. 

 Using the words in the accepted sense, which implies 

 advance, it is impossible to say that the modern lycopods 

 are more evolved than the fossil ones. Both in the 

 structure of their wood and in their complexity of fructi- 

 fications, as well as in their large size, the fossil trees 

 represent more highly organised organisms than do 

 the simple modern herbs. One remarkable genus of 

 the fossils (Lepidocarpon) had large fructifications 

 which almost amounted to seeds, while to-day the true 

 lycopods have only simple spores. It appears that 

 not only do individuals have a lifetime of waxing and 

 waning, but so do families as a whole, for it is certainly 

 true that in the time of the Coal Measures one of the 

 most numerous, successful, and dominant types w r as the 

 Lycopod family, which now is represented by few and 

 small species. 



A history almost parallel to this belongs to the other 

 great pteridophytio tree group of the Coal Measures 



